摘要:
A method for communicating channel estimates on a plurality of subcarriers between a transmitting device and a receiving device. The transmitting device determines a channel estimates on a plurality of subcarriers and then encodes the channel estimates into at least one encoded channel waveform. Then the transmitting device transmits the at least one encoded channel waveform to the receiving device.
摘要:
A method for communicating channel estimates on a plurality of subcarriers between a transmitting device and a receiving device. The transmitting device determines a channel estimates on a plurality of subcarriers and then encodes the channel estimates into at least one encoded channel waveform. Then the transmitting device transmits the at least one encoded channel waveform to the receiving device.
摘要:
A method for communicating a plurality of data streams between a transmitting device with multiple transmit antennas and a receiving device, is disclosed. The method comprises determining a list consisting of a subset of the multiple transmit antennas on which the transmitting device will transmit data, determining a set of power weightings, providing the set of power weightings and the list of the subset of the multiple transmit antennas to the transmitting device, weighting a plurality of data streams by the power weightings, and transmitting the power weighted data streams on the subset of the multiple transmit antennas to the receiving device. Another aspect of the invention comprises maintaining a codebook consisting of a plurality of transmit weight vectors at both the transmitting device and the receiving device. The method also comprises determining a list consisting of a subset of the plurality of transmit weight vectors which to use for transmitting the multiple data streams, determining a set of power weightings to be use for each data stream, providing the set of power weightings and the list of the subset of the plurality of transmit weight vectors to the transmitting device, and weighting the data streams by the power weightings and beamforming the data streams with the subset of the plurality of transmit weight vectors.
摘要:
A method and apparatus for performing spatial-division multiple access within a communication system is provided herein. During operation, nodes will return null subspace information along with their channel subspace information. The null subspace is similar to the channel subspace except that the null subspace information directs a base station to the matrix in a predefined codebook that results in minimum power being received at the node. The null subspace for each node is taken into consideration when communicating with a particular node.
摘要:
In a wireless communication system, a method and apparatus for closed loop transmission is disclosed. In accordance with the preferred embodiment of the present invention, a time frequency portion of an uplink frame is dynamically reserved as a sounding zone for uplink channel sounding. A first message is transmitted to a first subscriber station in a downlink frame assigning a time-frequency resource within the sounding zone, and a sounding waveform. Furthermore, a signal is received from the subscriber station within the assigned time-frequency resource, a partial channel response is determined from the received sounding signal, and the subsequent transmission to the subscriber station is tailored based on the at least partial channel response.
摘要:
Pilot sequences are constructed from distinct “classes” of chirp sequences that have an optimal cross correlation property. Utilization of chirp sequences for pilot sequences results in pilot sequences that have optimal or nearly-optimal cross correlation and auto-correlation properties.
摘要:
Cyclic-shift diversity transmission and optional per-subcarrier transmit beamforming within a same time interval (e.g., OFDM symbol interval) takes place. The CSD transmission technique circularly shifts the IFFT output prior to any cyclic prefix insertion and has the effect of putting a subcarrier and antenna dependent phase shift in the effective channel response from each transmit antenna. To properly perform transmit adaptive array (TXAA) transmission within an OFDM symbol interval that is being circularly shifted by the CSD transmission technique, the TXAA weights will account for the frequency domain phase shift created by the CSD circular shift operation.
摘要:
A system (10) and method (50) of operating a wireless communication system between a transmit device (12) employing an array of transmit antennas and a receiver (15) can include transmitting (52) a beamformed signal with antenna weights computed based on knowledge of a plurality of channels forming an aggregate channel and computing (54) a set of characteristics for the aggregate channel such as a power delay profile, a frequency correlation, or an expected beamforming gain of the aggregate channel. Characteristics can also be based on factors among a number of transmit antennas, a beamforming weight application delay value, an expected Doppler profile, or an expected delay profile of the propagation channel. The method can further determine (58) a channel estimator based on the computed set of characteristics, receive (62) the beamformed signal, and compute (64) an aggregate channel estimate as a function of the channel estimator and the beamformed signal.
摘要:
To address the need for a receiver that provides good performance during poor channel conditions yet reduces the computational complexity of existing ML receivers, a method and apparatus for MIMO joint detection and decoding is provided herein. In accordance with the preferred embodiment of the present invention, a low-complexity linear filter method is first utilized by the receiver. However, a higher-complexity non-linear method is utilized when the performance of the linear method is not adequate, for example, during poor channel conditions. In order to reduce the complexity of the non-linear decoding method, the distances to a much smaller set of candidate constellation points are computed than with prior-art decoding methods. This is made possible by the fact that some bits decoded with higher confidence utilizing the output of a linear filter method can help the decoding of the other bits.
摘要:
In a wireless communication system, a method and apparatus for reference signal selection is disclosed. In accordance with the preferred embodiment of the present invention, a first reference signal in a first cell is pseudo-randomly selected from a predetermined limited set of reference signals for transmission on a first channel resource. A second reference signal in the cell is pseudo-randomly selected from the predetermined limited set of reference signals for transmission on a second channel resource, where the predetermined limited set of reference signals is common among the first cell and at least a second cell.